1. Field of the Invention
This invention relates to an envelope blank forming machine and more particularly to an envelope blank forming machine for making either generally rectangular booklet type envelope blanks or generally diagonal type envelope blanks.
2. Description of the Prior Art
Machines for making booklet type envelope blanks are known. Other machines for making diagonal envelope blanks are also known. Web attachments for open end blanks as well as booklet blanks are also known.
U.S. Pat. No. 3,954,213 discloses a turnbar apparatus for turning a strip from a web from a horizontal plane to a vertical plane to adjust the entry angle of the strip as it is fed into the blank forming machine. The turnbars are mounted on separate supports and are adjustable relative to each other.
U.S. Pat. No. 2,951,408 discloses apparatus for forming only diamond or diagonal envelope blanks from a strip where the strip is fed to the machine at an angle to the axis of the blank forming machine. A means to adjust the angular relationship of the cutting knives and the shape of the diamond or diagonal blanks is also disclosed. The apparatus of conveying, shaping, driving, supporting and adjusting various components of the machine disclosed in U.S. Pat. No. 2,951,408 is incorporated herein by reference.
There is a need to provide an envelope blank forming machine that uses some of the same components for forming either generally rectangular booklet envelope blanks or generally diagonal envelope blanks. There is also a need to provide means to retract certain components when not required to form a particular envelope blank and to further substitute certain components in the same stations for the production of envelope blanks of a particular configuration.